1. Field of the Invention
This invention relates to optic disc analysis which technic is a useful aid in glaucoma detection. More specifically, a comparator apparatus and diagnosis is described by which two eye fundus photographic slides are superimposed so that blood vessel changes over substantial periods of time are monitored. Evaluation of these photographic slides is of particular importance as there is a large and significant collection of monoscopic eye fundus slides.
2. Disclosure Information Statement
In preparation for this application several searches were conducted. These included a computerized search of a medical literature database (MEDLINE), a computerized search of a patent database (DERWENT), and a manual pre-examination patentability search. These various searches did not uncover any highly relevant references. The manual search entailed a review of the following classes and subclasses:
______________________________________ Class Subclasses ______________________________________ 351 7 and 206 354 62 128 745, 665, 666 and 667 ______________________________________
The search uncovered the following patents:
______________________________________ U.S. Pat. No. Inventor Date of Issue ______________________________________ 4,249,825 Shapiro 2/10/81 Of Interest Only 4,402,325 Sawa 9/6/83 4,166,695 Hill et al 9/4/79 3,804,529 Kilmer et al 4/16/74 3,478,658 Yow Jiun Hu et al 11/18/69 2,573,464 Lowenstein et al 10/30/51 ______________________________________
In U.S. Pat. No. 4,249,825, Shapiro discloses a photographic-based system which looks at blood vessel image changes in time where use of special dyes are inherent as is the rapid time sequence.
No patent was found dealing with a long time period recording and comparison of fundus blood vessel images, or with any dual projector dual filter apparatus. Other patents found and listed above were considered merely of interest.
In opthamology, the practice of obtaining photographic slides of the eye fundus region is in general use to monitor optic disc deterioration. In glaucoma, this deterioration is evidenced by optic atrophy with glaucomatous cupping. It has long been felt that, utilizing existing patient archival material for displacement of optic dis vasculature, would be highly desirable. Until the apparatus and method of the present invention, no simple comparator other than visual side-by-side comparisons of slides, was available for use with the patient archival material.